In various industrial applications, scaffolding is erected in order to give workers access to elevations above ground. For example, in the installation of aluminum siding on the exterior of housing, scaffolding is required to enable workers to move up and down adjacent the side of the house. In such installation, the scaffolding is typically erected through the use of pump jack poles which are spaced apart alongside the house and secured to the house by means of braces. Pump jacks ride up and down on the poles and support a scaffold platform therebetween on which the workers stand. This scaffold platform typically comprises a pair of metal side rails, usually I-beam rails, held in parallel spaced relation by a plurality of spaced transverse hollow rungs upon which metal or wooden planks are placed and secured to provide the floor of the platform. These rungs may have a square cross-section to provide a plurality of flat upper surfaces in the same plane upon which the wooden planks may rest and be supported in place.
In order to protect the workers against falls, guarding means, such as guard rails or guard walls are erected from the scaffold platform on either or both sides of the workers. It is important that such guarding means be easy to assemble and attach to the platform and yet be firmly held in place without likelihood of detachment despite great outwardly applied pressure once assembled to the platform.
One such scaffold safety system is described and claimed in my U.S. Pat. No. 4,869,343. In accord with this scaffold safety system, one or more guard rail modules are erected along one or both sides of the platforms. Each guard rail module comprises a pair of spaced vertical guard posts connected by a horizontal hand rail. Each vertical post is retained by a coupling member which is clamped to a side rail of the platform. A planar panel may also be fastened to the post and handrail portions of each guard rail module to provide a guard wall therebetween.
The coupling member itself is described and claimed in my U.S. Pat. No. 4,856,616 and comprises an adjustable clamp having a pair of upper and lower lipped flange members which overlap the top and bottom flanges of an I-beam side rail of the scaffold platform. A fastening means passes through central web means of this adjustable clamp and bears against the outer side of this I-beam rail. A pair of apertures in the upper flange member of the clamp are shaped to receive and retain a pair of guard posts in side-by-side upright orientation.
Although this coupling member has been quite satisfactory for its intended purpose, it has been found that the alignment of the upper and lower flange members and the overlapping and clamping of these flange members to the I-beam rail is somewhat cumbersome and time consuming. In addition, the separate components of the coupling member may become lost or misplaced, and there is also a danger that the guard rail posts may accidentally be lifted out of their retaining apertures, or otherwise become separated from the coupling member, during use.
Accordingly, it is an object of the invention to provide a system for coupling a guarding means to a scaffold platform by which the coupling may be quickly and easily accomplished.
Another object of the invention is to provide a scaffold safety, system in which guard posts may be quickly and firmly coupled to a scaffold platform without danger that the posts may become separated from the coupling means.
A further object of the invention is to provide means for coupling guard posts to a scaffold platform in a manner which positively and securely retains the guard post in vertical orientation despite great pressure applied to the post in a direction away from the platform.
In another type of scaffolding arrangement, shown in my U.S. Pat. No. 4,805,618, upper and lower scaffold platforms traverse the spaced apart pump jack poles in opposite directions from a plane defined by the poles. The safety system shown in this patent includes a net wall which spans the gap between the upper and lower platforms. A plurality of individual clamps serve to attach the upper edge of the net wall to the upper platform and the lower edge of the net wall to the lower platform. This net wall not only protects the workers against falls, but also functions to catch and prevent tools and materials from falling to the ground below. However, it is somewhat inconvenient and time consuming to attach this net wall to these platforms by this plurality of clamps while standing on the lower platform.
Accordingly, it is a still further object of the invention to provide guard post coupling means which may be used to quickly and firmly attach a guard post to a scaffold platform in either vertical or horizontal orientation relative to the platform. The upper and lower edges of the net wall may then be preassembled to guard posts which may thereafter be quickly attached with horizontal orientation to the upper and lower platforms by workers standing on the lower platform.